Finding the Fourth Proportional to 1,580.65, 2,181.30 and 917.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,580.65 : 2,181.30 = 917.89 : x
2. Step 2: Convert to fraction form
   1,580.65/2,181.30 = 917.89/x
3. Step 3: Cross multiply
   1,580.65x = 2,181.30 × 917.89
4. Step 4: Simplify right side
   1,580.65x = 2,002,193.46
5. Step 5: Solve for x
   x = 2,002,193.46/1,580.65
6. Step 6: Final answer
   x = 1,266.69